1. Field of the Invention
This invention relates to an archery bow sight, and more particularly concerns an adjustable range finding sight for mounting on an archery bow.
2. Description of the Prior Art
Mastery of the art of archery is extremely difficult as many variables affect the accurate delivery of an arrow to the archer's desired target. The greatest variable is the accurate estimation of the distance the arrow is to travel to the target. An arrow moves relatively slow and falls to earth at an accelerating rate as it approaches the target. The trajectory of the archer's arrows requires extreme accuracy in range estimation in order to effectively place an arrow in a desired target.
The use of a sight pin in conjunction with a peep sight on the string of a bow can provide accuracy if the exact range to the target can be ascertained.
Various bow sights have been disclosed for increasing the archers accuracy. U.S. Pat. No. 2,001,470 issued May 14, 1935 to Nyvall shows a folding bow with a top and bottom mirror acting as a periscope to reflect an image of the target to the eye of the archer. The lower mirror is rotationally articulated to align cross hairs on the lower mirror with the target. The lower mirror must be rotated to pre-arranged positions which relate to various distances which the archer must estimate by other methods.
U.S. Pat. No. 3,163,697 issued Dec. 29, 1964 to White shows a dual spaced mirror device arranged such that the viewer will simultaneously see both a real and a reflected target image. As a viewer looks at the target, a slide is manipulated until the real and reflected images are both seen at the same height. At this position the bow is aimed at the target and is properly positioned such that an arrow will travel the proper trajectory to the target.
U.S. Pat. No. 3,524,440 issued Aug. 18, 1970 to Hill shows a mirror sighting device with an upper and lower mirror with cross hairs on one of the mirrors. The lower mirror is focused on the target while the upper mirror is focused on the lower mirror and reflects the target image to the archers eye. The mirror mounting the cross hairs may be adjusted vertically to compensate for distance to the target.
U.S. Pat. No. 2,788,701 issued Apr. 16, 1957 to Browning, shows a device incorporating multiple mirrors mounted below a single upper mirror for reflecting the image of the target and transmitting the image to the eye at various levels to facilitate trajectory adjustment of the bow for delivery of an arrow to the target.
U.S. Pat. No. 4,507,874 issued Apr. 2, 1985 to Brown, shows a bow sight characterized by a periscope device enclosing a top mirror and a bottom mirror to direct an image of a target to the eye of the archer. A compensating mirror is also mounted in the periscope in parallel adjustment relationship with respect to the top and bottom mirrors. A split target image is viewed in the fixed bottom mirror and comparison of this split image facilitates raising the bow to a proper angle in order to compensate for the trajectory of an arrow.
U.S. Pat. No. 4,555,856, issued Dec. 3, 1985 to Brown, is a continuation-in-part of the earlier '874 patent and shows a bow sight which includes a housing enclosing a bottom mirror, a top mirror mounted in spaced relationship in the housing with respect to the bottom mirror and a narrow compensating mirror positioned in the housing in close proximity to the bottom mirror. The top and bottom mirrors are mounted in substantially parallel relationship at approximately a 45 degree angle in the housing, and a top mirror and the compensating mirror are pivotally mounted with the compensating mirror adjustably responsive to manipulation of a lever from a calibrated position. The target image segment projected from the top mirror to the bottom mirror is compared to the target image segment projected from the compensating mirror to the bottom mirror and the lever is moved in order to provide the necessary adjustment to align the segments and determine the proper trajectory for accurately delivering an arrow to the target.
U.S. Pat. No. 4,979,309 issued Dec. 25, 1990 to Oligschlaeger discloses a bow sight having two mirrors in periscope arrangement, the upper mirror being tiltable in response to an archer-manipulated cam. Tilting of the mirror brings the target into view and simultaneously positions an aiming pin located below the lower mirror.
Numerous drawbacks have existed in the reliability and effective use of prior art sighting devices for archery bows. The need remains in the archery industry for a sight readily adaptable for long bows, recurve bows, compound bows, cross bows, and other similar projectile propelling devices of interest, which can accurately determine the distance between the viewer and the target and which facilitates positioning of a sight pin to the proper trajectory for the arrow to the target. The primary goal of this invention is to fulfill this need.
Another object of the invention is to provide a bow sight which is applicable to various bows and which uses adjustable top and bottom mirrors in cooperation with an adjustable sight pin to determine the distance to the target and compensate for the arrow trajectory.
Yet another object of this invention is to provide an improved range finder device cooperating with a sighting device for various bows, which range finder device is characterized by a frame carrying a bottom mirror and a pivotably adjustable top mirror.
A further object of the present invention is to provide a sight of the aforesaid nature which is automatically on target at distances between about 8 and 30 yards with a slow bow and 50 yards or more with a very fast bow, and has a range finder to cope with greater distances without any moving parts.
A still further object of this invention is to provide a bow sight of the aforesaid nature of simple and rugged design amenable to low cost manufacture.
These and other beneficial objects and advantages will be apparent from the following description.